Automatic locking means for keyboards



June 24, 1958 E. s. LARSON ETAL 2,840,216

AUTOMATIC LOCKING MEANS FOR KEYBOARDS Filed Feb. 5, 1940 2 Sheets-Sheet1 INVENTOR. EDWARD S. LARSON CARL A. LEVIN WWW ATTORNEY.

June 24, 1958 E. s. LARSON ETAL v AUTOMATIC LOCKING MEANS FOR KEYBOARDS2 Sheets-Sheet 2 Filed Feb. 5, 1940 qtqatq a u mum? INVENTOR. EDWARD S-LARSON CARL A. LEVIN AMI/MW ATTORNEY.

FIG. 2'

United States Patent AUTOMATIC LOCKlNG MEANS FOR KEYBOARDS Edward S.Larson and Carl A. Levin, Chicago, 111., as-

signors to the United States of America as represented by the Secretaryof the Navy Application February 5, 1940, Serial No. 317,456

8 Claims. (Cl. 1974) This invention relates to electromechanical codingand decoding apparatus having a coding unit and a unit to record orprint characters in response to operation of the coding unit, andparticularly to means for preventing further operation if the printingunit fails to function.

The primary object of this invention is to prevent continued operationof the coding device when printing of characters in response to suchoperation is not being effected.

Other objects will become apparent from the following description whenread in connection with the accompanying drawings, wherein:

Fig. 1 depicts schematically those elements of the coding unit directlyconcerned in the present invention;

Fig. 2 is complementary to Fig. 1 and illustrates schematically thoseparts of the printing unit wherein the present invention is embodied.

The subject matter of this application is intended to be incorporated inthe apparatus shown and claimed as a complete assembly in theapplication of Larson, Levin and Thienemann, Serial No. 317,454, filedFebruary 5, 1940, having been developed to insure that non-printing ofcharacters should be immediately brought to the attention of theoperator. This is essential since otherwise the characters in a codedmessage would not correspond throughout with the positions of certainelements of the mechanism and hence decipherment of the message would beimpossible.

The complete system comprises a coding unit having variable randomcircuit mechanisms of a type well known in this art, whereby thecircuits are sporadically changed, and a printing unit controlled bycurrent transmitted through the said circuits whereby to record acharacter each time the coding unit is operated.

The parts of the coding unit involved in the present invention are shownschematically in Fig. 1. Shaft 3 is continuously driven by a motor (notshown) and is drivingly engageable with cam sleeve 4 by a clutch 5 ofthe type fully shown and described in the patent to A. H. Reiber,2,019,505, November 5, 1935. This clutch has friction washers 6 thatslide on disk 7 so long as latch 8 is engaged with lug 9 on clutchlocking lever 10 which has a finger 11 engaged with a lug 12 on disk 7.However, when latch 8 is disengaged from lug 9, spring 13 frees finger11 from lug 12 and the friction washers drive cam sleeve 4 a few degreesuntil a positive mechanical clutch (not shown) is engaged to provide apositive drive. Roller 14 rides up cams 15 to rock lever 10 about pivot16 and reengage latch 8 with lug 9 after 180 of rotation of cam sleeve4, the above-mentioned mechanical clutch being disengaged immediatelybefore the roller 14 rides up cam 15.

Sleeve 4 carries a plurality of cams, of which cams 17 and 18 only areof present concern, and these are disposed to close contacts 19 and 20,respectively. It is to be kept in mind that the showing in Fig. 1 isschematic only and that cams 17 and 18 are actually double, to

2,840,216 Patented June 24, 1958 close contacts 19 and 20 in the courseof each of rotation of sleeve 4.

The character keys 2 are pivotally mounted and each key is effective toclose an individual pair of contacts 21 that is in a circuit through themaze of random circuits represented at 61, the direction in which thecurrent traverses the random circuits being reversible by a switch 22,the current passing from left to right through 61 when coding and fromright to left when decoding. It will be observed that one side of eachof the contacts 21 is connected through conductor 23 to one side ofcontacts 19 whereby the circuit is not operatively completed until cam17 closes contacts 19. As described in the above-mentioned applicationof Larson, Levin and Thienemann, means are provided to hold a characterkey 2 depressed until the cam 17 has closed contacts 19 and the otherphases of an operating cycle have been completed.

Extending under all of the character keys 2 is a universal bail 24pivotally mounted at its ends to be rocked downwardly when a key 2 isdepressed. By mechanism fully shown in the patent to Reiber, supra, thebail 24 is connected to rod 25 to release latch 8 and permit rotation ofthe cam sleeve 4. Underlying the ends of bail 24 is a longitudinallyslidable locking blade 26 having cut out portions 27 that normallyunderlie the arms of bail 24 and permit the bail to operate. However,under certain conditions to be hereinafter described, the keyboardlocking magnets 28 are energized and attract armature 29 to which isconnected one end of pivoted lever 30 that is also connected to lockingblade 26 to slide the locking blade longitudinally and move the cut outportions 27 away from bail 24 whereby to prohibit rocking of the bailand prevent depression of the keys 2. When the operator notes that thekeys 2 cannot be depressed he is warned that the mechanism is locked andrequires attention.

Referring now to Fig. 2, it will be seen that the printing unit includesa rotatable shaft 31 that is connectible through jaw clutch 32 with amotor (not shown). The driven jaw 33 of clutch 32 carries a camming lug34 that engages in a camming slot in clutch throw-out lever 35 todisengage clutch 32, the lever 35 being held in clutch disengagingposition by a latching lever 36. When any pair of contacts 21 is closed,and the circuit is completed by closure of contacts 20, an impulse istransmitted through conductor 37 to some one of the type bar selectormagnets 38 to select a type bar for operation. The printing unit is verysimilar to that described in bulletin No. 109 of the TeletypeCorporation, dated April 1926, except that type bars are selected foroperation directly instead of code bars being selected as in thecommercial printing telegraph system. However, the driving means in Fig.2 above set forth is identical with that fully disclosed in the saidbulletin No. 109. It is seen in Fig. 2 that each of the type barselector magnets 38 is connected by conductors 39 and 40 to a clutchrelease magnet 41 which, when energized, rocks latching lever 36 andallows a biasing spring to move the clutch throwout lever 35 out ofengagement with lug 34, thereby permitting spring 42 to engage the jawsof clutch 32 and drive shaft 31.

Fixed on shaft 31 is a cam 43 having a cut out portion 44 so disposedthat the cam follower 45 drops into the cut out portion 44 when lug 34is engaged with lever 35. When the cam follower 45 is lying in cut outportion 44 contacts 46 close a circuit through conductors 47 and 48 tocontacts 20 and keyboard locking magnets 28, re-.

spectively. Since the circuit to locking magnets 28 is not completeduntil contacts 20 are closed, the closure of contacts 46 does not byitself lock the keyboard. When a key 2 is depressed and current flows tothe selector magnets 38 and to clutch release magnet 41, the jaws ofclutch 32 engage and immediately cam follower 45 rides up on cam 43 toseparate contacts 46 and break the circuit to locking magnets 28 beforethe contacts are closed. However, if for any reason, the clutch 32 isnot released to drive shaft 31, the circuit at contacts as remainsclosed and therefore as soon as cam 18 closes contacts 20, the magnets28 are energized and locking blade 26 is moved to lock the keyboard. i

Lever has its end 49 disposed to close contacts 50 and complete aholding circuit through locking magnets 28. Keyboard locking magnets 28may be deenergized by means of release key 51 that controls contacts 52directly connected by conductor 53 to clutch release magnet 41. Whencontacts 52 areclosed the clutch release magnet 41 is energized, clutch32 is engaged and shaft 31 is rotated to break the circuit at contacts46, all inde pendently of the circuits controlled by the character key2.

Certain features are indicated in the drawings that are not directlyconcerned with the present invention, such as contacts 54 that areclosed to lock the keyboard when the end of a line is reached; contacts55 and magnet 56 that insert an extra space after every fifth characterthat is recorded; contacts 57 that are closed to lock the keyboard whenthe switch 22 is not fully thrown to either the en cipher or decipherposition, and contacts 58 that are closed when the mechanism forchanging the random circuits 21 is not conditioned for operation, allthe above being fully set forth in the said application of Larson, Levinand Thienemann.

We claim:

1. Ciphering mechanism and printing mechanism responsive to operation ofsaid ciphering mechanism, said ciphering mechanism including a rotatablecam sleeve, clutch means engageable to drive said sleeve, means todisengage said clutch means cyclically, a plurality of char acter keyseach mounted on a key lever, a member operable by each of said keylevers connected to release said clutch means for driving engagementwith said sleeve, means to lock said member against operation, a firstelectromagnet to move said locking means to locking position, a pair ofcontacts individual to each said key disposed to be closable by therespective key lever, a first cam on said sleeve, character pulsecontacts disposed to be closable by said cam and connected in serieswith each of said pairs of contacts, a second cam on said sleeve, lockpulse contacts closable by said second cam, said printing mechanismincluding a rotatable cam shaft, clutch means engageable to drive saidshaft, means cyclically engageable with an element of the printingmechanism clutch means to disengage said element and retain the samelatched in disengaged position, a second electromagnet disposed torelease said element from latched position to effect driving of said camshaft, means including said character pulse contacts connecting all saidpairs of contacts to energize said second electromagnet each time anyone of said character keys is depressed, a third cam on said shaft, apair of locking contacts having a portion contacting said third camwhereby said contacts are opened when said shaft revolves, meansconnecting said lock pulse contacts and said locking contacts toenergize said first electromagnet when said lock pulse contacts and saidlocking contacts are concurrently closed; an additional pair ofcontacts, means to close said additional contacts and means connectingsaid additional contacts and said lock pulse contacts to energize saidfirst electromagnet when said additional contacts and said lock pulsecontacts are closed concurrently.

2. Ciphering mechanism and printing mechanism responsive to operation ofsaid ciphering mechanism, said ciphering mechanism including a rotatablecam sleeve, clutch means engageable to drive said sleeve, means todisengage said clutch means cyclically, a plurality of character keyseach mounted on a key lever, a member operable by each of said keylevers connected to release said clutch means for driving engagementwith said sleeve, means to lock said member against operation, a firstelectromagnet to move said locking means to locking position, a pair ofcontacts individual to each said key disposed to be closable by therespective key lever, a first cam on said sleeve, lock pulse contactsdisposed to be clcsable by said cam; said printing mechanism including arotatable cam shaft, clutch means engageable to drive said shaft, meanscyclically engageable with an element of the printing mechanism clutchmeans to disengage said element and retain the same latched indisengaged position, a second electromagnet disposed to release saidelement from latchedposition to effect driving of said I cam shaft,means responsive to operation of any one of said keys to energize saidsecond electromagnet, a second cam on said shaft, said cam beingsubstantially circular and having a depression, locking contacts havinga portion that lies in the depression in said second cam to permit saidlocking contacts to close when said shaft is stationary but to open saidlocking contacts when said shaft revolves; and means connecting saidlock pulse contacts and said locking contacts to energize said firstelectromagnet when both lock pulse and locking contacts are concurrentlyclosed.

3. Ciphering mechanism and printing mechanism responsive to operation ofsaid ciphering mechanism, said ciphering mechanism including a rotatablecam sleeve, clutch means engageable to drive said sleeve, means todisengage said clutch means cyclically, a plurality of charatcer keyseach mounted on a key lever, a member operable by each of said keylevers connected to release said clutch means for driving engagementwith said sleeve, means to lock said member against operation, a firstelectromagnet to move said locking means to locking position, a pair ofcontacts individual to each said key disposed to be closable by therespective key lever, a cam on said sleeve, lock pulse contacts disposedto be closable by said cam; said printing mechanism includingselfclosing locking contacts, means to open said locking contacts whensaid printing mechanism operates; means connecting said locking contactsand said lock pulse contacts to energize said first electromagnet whenboth lock pulse and locking contacts are closed concurrently, and meansto effect a cycle of operation of said printing mechanism when any oneof said keys is depressed.

4. Ciphering mechanism and printing mechanism responsive to operation ofsaid ciphering mechanism, said ciphering mechanism comprising aplurality of character keys, means operable in a discrete cycle inresponse to the depression of any one of said keys, said means includinga cam, lock pulse contacts closable by said cam once each cycle ofoperation, means to lock said keys against operation, a firstelectromagnet to actuate said locking means; said printing mechanismincluding a rotatable cam shaft, clutch means engageable to drive saidshaft, means to disengage said clutch means on completion of eachrotation and latch the same in disengaged position, a secondelectromagnet to unlatch said clutch means, means controlled by any oneof said keys to energize said second electromagnet, a second cam on saidcam shaft, self-closing locking contacts disposed to be opened by saidsecond cam when said shaft rotates, and means connecting said lock pulsecontacts and said locking contacts to energize said first electromagnetwhen said lock pulse and said locking contacts are concurrently closed.

5. Ciphering mechanism and'printing mechanism connected tobe controlledby operation of said ciphering mechanism, said ciphering mechanismcomprising a plurality of character keys, means operable in a discretecycle in response to the depression of any one of said keys, said meansincluding a cam, lock pulse contacts closable by said cam once eachcycle of operation, means to lock said keys against operation, anelectromagnet controlled by said contacts to actuate said locking;means;

said printing mechanism including a rotatable cam shaft, and meansoperative when said shaft is stationary to energize said electromagnetwhen said lock pulse contacts are closed.

6. Ciphering mechanism and printing mechanism connected to be controlledby operation of said ciphering mechanism, said ciphering mechanismcomprising a plurality of character keys, means to lock said keysagainst operation, an electromagnet to actuate said means, self-openinglock pulse contacts, means responsive to operation of any one of saidkeys to close said contacts momentarily, and means in said printingmechanism connected to cooperate with said lock pulse contacts undercertain non-operating conditions of said printing mechanism to energizesaid electromagnet.

7. Ciphering mechanism and printing mechanism controlled thereby,comprising a respective rotatable shaft in each said mechanism, alocking circuit including a pair of contacts closable by rotation of theshaft in said cipher- 6 ing mechanism and in series therewith a pair ofcontacts in said printing mechanism closed only when the shaft in saidprinting mechanism is at rest, and means actuated by current throughsaid locking circuit to pre vent operation of said ciphering mechanismwhen both pairs of contacts are closed simultaneously.

8. Ciphering mechanism and printing mechanism controlled thereby,comprising a respective rotatable shaft in each said mechanism, andmeans controlled by the simultaneous operation of the shaft in saidciphering mechanism and non-operation of the shaft in said printingmechanism to lock said ciphering mechanism against operation.

References Cited in the file of this patent UNITED STATES PATENTS

